I can't recall seeing this mentioned before, but recently I had the need to use the same greyscale image in both positive and negative versions on the same material. Rather than use two bitmaps, I looked for a material room method of inverting the image, and the above shows my solution using two math nodes. Hope someone finds this useful. -- Mark

Inverting can be very usefull. If you plug the image in the value_2 of the subtraction you don't need the Abs operation. Black = 0, white = 1 therefor: Inverse a = 1 - a = abs(a-1) Stefan

Well Duh Thanks quinlor, obvious now you mention it. -- Mark

Attached Link: http://www.renderosity.com/messages.ez?ForumID=12356&Form.ShowMessage=884761

I was involved in a similar discussion almost two months ago that you can find at http://www.renderosity.com/messages.ez?ForumID=12356&Form.ShowMessage=884761. It includes a couple of screenshots from the Material room.

Umm,I keep forgetting people aren't as used to these sorts of concepts as others are... Maybe i should go through all the nodes and play with them and report on my findings, I''ve already gotten some really nice textures with it...

heyas; do what? make the math subtract be 1 - input map? or make it 0 - input map??

To invert the map it is: 1 - input map Stefan

ummm... it's not 0 - input?

Think of the numbers as percentages of Gray. 0 = White 0.1 = 10% Gray 0.5 = 50% Gray 0.9 = 90% Gray 1 = 100% Gray All negative numbers will give you white, all numbers greater 1 will give you black. The usefull range is 0 to 1. To invert a grayscale white must become black, 10% gray must become 90% gray. 50% gray should remain 50% gray. To do this use 1 - input. Stefan

Sorry, I messed this up: 0 = black and 1 = white 0.1 = 90% gray 0.9 = 10% gray But the math is the same.

oh. i'll take your word for it ;)

Bloodsong, I could show you a pic of the invert I used for my Balrog's material nodes, but there are about fifteen nodes in the texture, and it would be kinda hard to isolate it. ^_^ It's even messier-looking than my desktop.